The present invention relates, in general, to powder paint delivery apparatus and methods.
Paint coatings are typically applied to large objects, such as automotive vehicle bodies, automotive vehicle parts and other objects in a closed paint booth. The automotive bodies or parts to be painted move through the booth in a sequential manner, typically via conveyor.
Paint applicators are disbursed throughout the booth and, are frequently in the form of programmed robotic applicators.
Although liquid spray paint has been frequently employed in the past, current technology is moving to powder paint coating application. In a typical powder paint application, powder from a bag or tote is supplied to at least one virgin powder hopper. A percentage of the output of the virgin hopper is supplied to one or more mix hoppers which also receive reclaimed overspray powder paint from the paint booth in a selected ratio.
The powder paint is transported from the virgin and mix hoppers through a network of multi-directional valves to the paint applicators. A control system controls the position of the multi-directional valves so as to enable 100% virgin powder paint to be supplied to one or more specific paint applicators in the paint booth, and/or 100% mixed powder paint from the one or more mix hoppers to one or more specific paint applicators in the paint booth.
If additional mix hoppers are employed, the ratio of reclaimed powder paint to virgin paint in such mix hoppers can be different from the primary or other mix hopper so that a different mix of virgin and reclaimed powder paint can be supplied to specific applicators in the paint booth.
In dense phase powder paint systems using positive air pressure to transport the powder from the hoppers to the paint applicators, applicator pumps generally have a pump chamber including a gas permeable member. Powder paint is supplied to the chamber along with a fluidizing gas, such as air. The fluidized dense phase powder is then discharged from the pump chamber to a paint applicator for disbursal over the object being painted.
Since paint booths typically employ a large number of separate paint applicators, the complexity of the valve and pump networks used to transport powder paint from virgin and mix hoppers to the individual paint applicators can be complex. This complexity necessarily results in frequent breakdown due to the number of components, the viscosity of the powder being transported through the transport systems which can lead to frequent clogging, etc. Production must be halted to repair any damaged or inoperative component in the powder paint transport system.
It would desirable to provide a powder paint delivery apparatus which addresses these deficiencies.